The bridge exercise helps lift and tighten lower body muscles

Try This: Engage the glutes, quadriceps and hamstrings with a lifting movement known as the bridge.

Tosca Reno shows you how to do the bridge: a great exercise that helps lift and tighten lower body muscles.

Tosca Reno shows you how to do the bridge: a great exercise that helps lift and tighten lower body muscles.

Rene Lynch

What do you think about when you're working out your glutes? If you're like most, you're just counting reps, waiting for the whole thing to be over. But fitness expert Tosca Reno, author of the new book "The Start Here Diet," says you could be cheating yourself out of gains if you don't focus your mind as well as your muscles.

The lower-body muscles are relatively powerful to begin with. As a result, you might be able to knock out a few sets of the bridge exercise without too much effort. But if you block out all distractions, focus on those muscles, and squeeze 'em like you're getting paid to do it ... suddenly a set of 10 repeats can leave you panting.

What it does

The bridge lifts, tightens and tones the glutes, quadriceps and hamstrings as you engage and isolate those muscles with a fluid lifting movement. It also offers a bit of a lower ab engagement if you remember to tighten those muscles as well. (Pretend you are bringing your belly button to your spine.)

What to do

Lie on your back, knees up, feet flat on the floor. Bring your heels as close to your butt as is comfortable, with hands at your side. Now squeeze the glutes, quads, abs and hamstrings, and raise your butt up. Pretend you are creating a rock-solid launching pad from your stomach to your knees. "Squeeze, squeeze, squeeze," Reno says. Hold the squeeze at the top, then bring the butt down in a controlled fashion. Don't lift so high that you put too much pressure on your neck and shoulders. You also do not want to arch your back excessively. Just lifting a few inches off the ground will engage those lower body muscles.

How much

Reno suggests doing these three times a week, working up to three sets of at least 20 reps per set. But remember: These are slow, methodical reps where all your focus is on the lower body — "Think about your glutes and engaging your core. Your core is tight" — and controlling the movement, Reno says.